Commit Graph

61 Commits

Author SHA1 Message Date
John Dyson
996c772f58 This is the kernel Lite/2 commit. There are some requisite userland
changes, so don't expect to be able to run the kernel as-is (very well)
without the appropriate Lite/2 userland changes.

The system boots and can mount UFS filesystems.

Untested: ext2fs, msdosfs, NFS
Known problems: Incorrect Berkeley ID strings in some files.
		Mount_std mounts will not work until the getfsent
		library routine is changed.

Reviewed by:	various people
Submitted by:	Jeffery Hsu <hsu@freebsd.org>
1997-02-10 02:22:35 +00:00
John Dyson
afa07f7e83 Change the map entry flags from bitfields to bitmasks. Allows
for some code simplification.
1997-01-16 04:16:22 +00:00
Jordan K. Hubbard
1130b656e5 Make the long-awaited change from $Id$ to $FreeBSD$
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore.  This update would have been
insane otherwise.
1997-01-14 07:20:47 +00:00
John Dyson
9b5a5d81be Prepare better for multi-platform by eliminating another required
pmap routine (pmap_is_referenced.)  Upper level recoded to use
pmap_ts_referenced.
1997-01-11 07:19:02 +00:00
John Dyson
d0aea04fe0 Let the VM system know that on certain arch's that VM_PROT_READ
also implies VM_PROT_EXEC.  We support it that way for now,
since the break system call by default gives VM_PROT_ALL.  Now
we have a better chance of coalesing map entries when mixing
mmap/break type operations.  This was contributing to excessive
numbers of map entries on the modula-3 runtime system.  The
problem is still not "solved", but the situation makes more
sense.

Eventually, when we work on architectures where VM_PROT_READ
is orthogonal to VM_PROT_EXEC, we will have to visit this
issue carefully (esp. regarding security issues.)
1996-12-30 05:31:21 +00:00
John Dyson
94328e9057 The code unnecessarily created an object with no handle up-front, which
has the negative effect of disabling some map optimizations.  This
patch defers the creation of the object until it needs to be at fault time.
Submitted by:	Alan Cox <alc@cs.rice.edu>
1996-12-28 22:40:44 +00:00
Joerg Wunsch
e9822d926c Make DFLDSIZ and MAXDSIZ fully-supported options.
"Don't forget to do a ``make depend''" :-)
1996-12-22 23:17:09 +00:00
John Dyson
7aaaa4fd5d Implement closer-to POSIX mlock semantics. The major difference is
that we do allow mlock to span unallocated regions (of course, not
mlocking them.)  We also allow mlocking of RO regions (which the old
code couldn't.)  The restriction there is that once a RO region is
wired (mlocked), it cannot be debugged (or EVER written to.)

Under normal usage, the new mlock code will be a significant improvement
over our old stuff.
1996-12-14 17:54:17 +00:00
John Dyson
851c12ff1d Change mmap to use OBJT_DEFAULT instead of OBJT_SWAP by default
for anonymous objects.  The system will automatically change the
type to SWAP if needed (for size or pageout reasons.)
1996-10-29 22:07:11 +00:00
John Dyson
fcae040bc0 Remove a bogus optimization in the mmap code. It is superfluous,
and at best is the same speed as the unoptimized code.  At worst, it
slows down trivial programs.
1996-10-24 02:56:23 +00:00
Poul-Henning Kamp
1111860c29 Remove a stale comment. 1996-10-13 07:16:50 +00:00
David Greenman
cd6eea255f Fixed bug with reversed trunc/round_page() in madvise...start must be
trunced, end must be rounded.
1996-09-19 10:12:41 +00:00
John Dyson
67bf686897 Backed out the recent changes/enhancements to the VM code. The
problem with the 'shell scripts' was found, but there was a 'strange'
problem found with a 486 laptop that we could not find.  This commit
backs the code back to 25-jul, and will be re-entered after the snapshot
in smaller (more easily tested) chunks.
1996-07-30 03:08:57 +00:00
David Greenman
0f281c28fa Slight performance tweak for previous commit. 1996-07-28 02:54:09 +00:00
John Dyson
bf6dfc7b35 Allow sequentially created mmap'ed anonymous regions to coalesce. There
is little or no reason to create a swap pager for small mmap's.  The
vm_map_insert code will automatically create a swap pager if the object
becomes too large.  This fix, per a request from phk.
1996-07-27 17:21:41 +00:00
John Dyson
feb32a8fa9 Remove experimental header file. My test-build must have picked it
up in an unexpected place.
Submitted by:	jkh
1996-07-27 04:06:11 +00:00
John Dyson
4f4d35edf0 This commit is meant to solve a couple of VM system problems or
performance issues.

	1) The pmap module has had too many inlines, and so the
	   object file is simply bigger than it needs to be.
	   Some common code is also merged into subroutines.
	2) Removal of some *evil* PHYS_TO_VM_PAGE macro calls.
	   Unfortunately, a few have needed to be added also.
	   The removal caused the need for more vm_page_lookups.
	   I added lookup hints to minimize the need for the
	   page table lookup operations.
	3) Removal of some bogus performance improvements, that
	   mostly made the code more complex (tracking individual
	   page table page updates unnecessarily).  Those improvements
	   actually hurt 386 processors perf (not that people who
	   worry about perf use 386 processors anymore :-)).
	4) Changed pv queue manipulations/structures to be TAILQ's.
	5) The pv queue code has had some performance problems since
	   day one.  Some significant scalability issues are resolved
	   by threading the pv entries from the pmap AND the physical
	   address instead of just the physical address.  This makes
	   certain pmap operations run much faster.  This does
	   not affect most micro-benchmarks, but should help loaded system
	   performance *significantly*.  DG helped and came up with most
	   of the solution for this one.
	6) Most if not all pmap bit operations follow the pattern:
		pmap_test_bit();
		pmap_clear_bit();
	   That made for twice the necessary pv list traversal.   The
	   pmap interface now supports only pmap_tc_bit type operations:
	   pmap_[test/clear]_modified, pmap_[test/clear]_referenced.
	   Additionally, the modified routine now takes a vm_page_t arg
	   instead of a phys address.  This eliminates a PHYS_TO_VM_PAGE
	   operation.
	7) Several rewrites of routines that contain redundant code to
	   use common routines, so that there is a greater likelihood of
	   keeping the cache footprint smaller.
1996-07-27 03:24:10 +00:00
John Dyson
f35329ac0f This commit is dual-purpose, to fix more of the pageout daemon
queue corruption problems, and to apply Gary Palmer's code cleanups.
David Greenman helped with these problems also.  There is still
a hang problem using X in small memory machines.
1996-05-31 00:38:04 +00:00
John Dyson
867a482d66 Initial support for mincore and madvise. Both are almost fully
supported, except madvise does not page in with MADV_WILLNEED, and
MADV_DONTNEED doesn't force dirty pages out.
1996-05-19 07:36:50 +00:00
John Dyson
b18bfc3da7 This set of commits to the VM system does the following, and contain
contributions or ideas from Stephen McKay <syssgm@devetir.qld.gov.au>,
Alan Cox <alc@cs.rice.edu>, David Greenman <davidg@freebsd.org> and me:

	More usage of the TAILQ macros.  Additional minor fix to queue.h.
	Performance enhancements to the pageout daemon.
		Addition of a wait in the case that the pageout daemon
		has to run immediately.
		Slightly modify the pageout algorithm.
	Significant revamp of the pmap/fork code:
		1) PTE's and UPAGES's are NO LONGER in the process's map.
		2) PTE's and UPAGES's reside in their own objects.
		3) TOTAL elimination of recursive page table pagefaults.
		4) The page directory now resides in the PTE object.
		5) Implemented pmap_copy, thereby speeding up fork time.
		6) Changed the pv entries so that the head is a pointer
		   and not an entire entry.
		7) Significant cleanup of pmap_protect, and pmap_remove.
		8) Removed significant amounts of machine dependent
		   fork code from vm_glue.  Pushed much of that code into
		   the machine dependent pmap module.
		9) Support more completely the reuse of already zeroed
		   pages (Page table pages and page directories) as being
		   already zeroed.
	Performance and code cleanups in vm_map:
		1) Improved and simplified allocation of map entries.
		2) Improved vm_map_copy code.
		3) Corrected some minor problems in the simplify code.
	Implemented splvm (combo of splbio and splimp.)  The VM code now
		seldom uses splhigh.
	Improved the speed of and simplified kmem_malloc.
	Minor mod to vm_fault to avoid using pre-zeroed pages in the case
		of objects with backing objects along with the already
		existant condition of having a vnode.  (If there is a backing
		object, there will likely be a COW...  With a COW, it isn't
		necessary to start with a pre-zeroed page.)
	Minor reorg of source to perhaps improve locality of ref.
1996-05-18 03:38:05 +00:00
Poul-Henning Kamp
aa8de40ae5 Another sweep over the pmap/vm macros, this time with more focus on
the usage.  I'm not satisfied with the naming, but now at least there is
less bogus stuff around.
1996-05-03 21:01:54 +00:00
David Greenman
8f2ec877b8 Force device mappings to always be shared. It doesn't make sense for them
to ever be COW and we need the mappings to be shared for backward
compatibilty.

Reviewed by:	dyson
1996-03-16 15:00:05 +00:00
John Dyson
5850152d95 Allow mmap'ed devices to work correctly across forks. The sanest
solution appeared to be to allow the child to maintain the same mapping as
the parent.
1996-03-12 02:27:20 +00:00
Peter Wemm
9154ee6aec Oops.. I nearly forgot the actual core of the length/rounding/etc fixes
that Bruce asked for.

These still are not quite perfect, and in particular, it can get
upset on extreme boundary cases (addr = 0xfff, len = 0xffffffff,
which would end up mapping a single page rather than failing), but
this is better code that I committed before.

(note, the VM system does not (apparently) support single mmap segment
sizes above 0x80000000 anyway)
1996-03-02 17:14:09 +00:00
John Dyson
de5f6a7765 1) Eliminate unnecessary bzero of UPAGES.
2) Eliminate unnecessary copying of pages during/after forks.
3) Add user map simplification.
1996-03-02 02:54:24 +00:00
Peter Wemm
dabee6fecc kern_descrip.c: add fdshare()/fdcopy()
kern_fork.c: add the tiny bit of code for rfork operation.
kern/sysv_*: shmfork() takes one less arg, it was never used.
sys/shm.h: drop "isvfork" arg from shmfork() prototype
sys/param.h: declare rfork args.. (this is where OpenBSD put it..)
sys/filedesc.h: protos for fdshare/fdcopy.
vm/vm_mmap.c: add minherit code, add rounding to mmap() type args where
it makes sense.
vm/*: drop unused isvfork arg.

Note: this rfork() implementation copies the address space mappings,
it does not connect the mappings together.  ie: once the two processes
have split, the pages may be shared, but the address space is not. If one
does a mmap() etc, it does not appear in the other.  This makes it not
useful for pthreads, but it is useful in it's own right for having
light-weight threads in a static shared address space.

Obtained from: Original by Ron Minnich, extended by OpenBSD
1996-02-23 18:49:25 +00:00
John Dyson
bd7e5f992e Eliminated many redundant vm_map_lookup operations for vm_mmap.
Speed up for vfs_bio -- addition of a routine bqrelse to greatly diminish
	overhead for merged cache.
Efficiency improvement for vfs_cluster.  It used to do alot of redundant
	calls to cluster_rbuild.
Correct the ordering for vrele of .text and release of credentials.
Use the selective tlb update for 486/586/P6.
Numerous fixes to the size of objects allocated for files.  Additionally,
	fixes in the various pagers.
Fixes for proper positioning of vnode_pager_setsize in msdosfs and ext2fs.
Fixes in the swap pager for exhausted resources.  The pageout code
	will not as readily thrash.
Change the page queue flags (PG_ACTIVE, PG_INACTIVE, PG_FREE, PG_CACHE) into
	page queue indices (PQ_ACTIVE, PQ_INACTIVE, PQ_FREE, PQ_CACHE),
	thereby improving efficiency of several routines.
Eliminate even more unnecessary vm_page_protect operations.
Significantly speed up process forks.
Make vm_object_page_clean more efficient, thereby eliminating the pause
	that happens every 30seconds.
Make sequential clustered writes B_ASYNC instead of B_DELWRI even in the
	case of filesystems mounted async.
Fix a panic with busy pages when write clustering is done for non-VMIO
	buffers.
1996-01-19 04:00:31 +00:00
Bruce Evans
f2c6b65bab Fixed 1TB filesize changes. Some pindexes had bogus names and types
but worked because vm_pindex_t is indistinuishable from vm_offset_t.
1995-12-17 07:19:58 +00:00
John Dyson
3048c51216 There was a bug that the size for an msync'ed region was not rounded
up.  The effect of this was that msync with a size would generally sync
1 page less than it should.  This problem was brought to my attention
by Darrel Herbst <dherbst@gradin.cis.upenn.edu> and Ron Minnich
<rminnich@sarnoff.com>.
1995-12-13 12:28:39 +00:00
John Dyson
a316d390bd Changes to support 1Tb filesizes. Pages are now named by an
(object,index) pair instead of (object,offset) pair.
1995-12-11 04:58:34 +00:00
David Greenman
efeaf95a41 Untangled the vm.h include file spaghetti. 1995-12-07 12:48:31 +00:00
Bruce Evans
cac597e4c0 Completed function declarations and/or added prototypes.
Staticized some functions.

__purified some functions.  Some functions were bogusly declared as
returning `const'.  This hasn't done anything since gcc-2.5.  For
later versions of gcc, the equivalent is __attribute__((const)) at
the end of function declarations.
1995-12-03 12:18:39 +00:00
Bruce Evans
d2d3e8751c Included <sys/sysproto.h> to get central declarations for syscall args
structs and prototypes for syscalls.

Ifdefed duplicated decentralized declarations of args structs.  It's
convenient to have this visible but they are hard to maintain.  Some
are already different from the central declarations.  4.4lite2 puts
them in comments in the function headers but I wanted to avoid the
large changes for that.
1995-11-12 06:43:28 +00:00
John Dyson
e17bed1226 First phase of removing the PG_COPYONWRITE flag, and an architectural
cleanup of mapping files.
1995-10-23 03:49:43 +00:00
John Dyson
02c04a2f6c Implement mincore system call. 1995-10-21 17:42:28 +00:00
David Greenman
24a1cce34f NOTE: libkvm, w, ps, 'top', and any other utility which depends on struct
proc or any VM system structure will have to be rebuilt!!!

Much needed overhaul of the VM system. Included in this first round of
changes:

1) Improved pager interfaces: init, alloc, dealloc, getpages, putpages,
   haspage, and sync operations are supported. The haspage interface now
   provides information about clusterability. All pager routines now take
   struct vm_object's instead of "pagers".

2) Improved data structures. In the previous paradigm, there is constant
   confusion caused by pagers being both a data structure ("allocate a
   pager") and a collection of routines. The idea of a pager structure has
   escentially been eliminated. Objects now have types, and this type is
   used to index the appropriate pager. In most cases, items in the pager
   structure were duplicated in the object data structure and thus were
   unnecessary. In the few cases that remained, a un_pager structure union
   was created in the object to contain these items.

3) Because of the cleanup of #1 & #2, a lot of unnecessary layering can now
   be removed. For instance, vm_object_enter(), vm_object_lookup(),
   vm_object_remove(), and the associated object hash list were some of the
   things that were removed.

4) simple_lock's removed. Discussion with several people reveals that the
   SMP locking primitives used in the VM system aren't likely the mechanism
   that we'll be adopting. Even if it were, the locking that was in the code
   was very inadequate and would have to be mostly re-done anyway. The
   locking in a uni-processor kernel was a no-op but went a long way toward
   making the code difficult to read and debug.

5) Places that attempted to kludge-up the fact that we don't have kernel
   thread support have been fixed to reflect the reality that we are really
   dealing with processes, not threads. The VM system didn't have complete
   thread support, so the comments and mis-named routines were just wrong.
   We now use tsleep and wakeup directly in the lock routines, for instance.

6) Where appropriate, the pagers have been improved, especially in the
   pager_alloc routines. Most of the pager_allocs have been rewritten and
   are now faster and easier to maintain.

7) The pagedaemon pageout clustering algorithm has been rewritten and
   now tries harder to output an even number of pages before and after
   the requested page. This is sort of the reverse of the ideal pagein
   algorithm and should provide better overall performance.

8) Unnecessary (incorrect) casts to caddr_t in calls to tsleep & wakeup
   have been removed. Some other unnecessary casts have also been removed.

9) Some almost useless debugging code removed.

10) Terminology of shadow objects vs. backing objects straightened out.
    The fact that the vm_object data structure escentially had this
    backwards really confused things. The use of "shadow" and "backing
    object" throughout the code is now internally consistent and correct
    in the Mach terminology.

11) Several minor bug fixes, including one in the vm daemon that caused
    0 RSS objects to not get purged as intended.

12) A "default pager" has now been created which cleans up the transition
    of objects to the "swap" type. The previous checks throughout the code
    for swp->pg_data != NULL were really ugly. This change also provides
    the rudiments for future backing of "anonymous" memory by something
    other than the swap pager (via the vnode pager, for example), and it
    allows the decision about which of these pagers to use to be made
    dynamically (although will need some additional decision code to do
    this, of course).

13) (dyson) MAP_COPY has been deprecated and the corresponding "copy
    object" code has been removed. MAP_COPY was undocumented and non-
    standard. It was furthermore broken in several ways which caused its
    behavior to degrade to MAP_PRIVATE. Binaries that use MAP_COPY will
    continue to work correctly, but via the slightly different semantics
    of MAP_PRIVATE.

14) (dyson) Sharing maps have been removed. It's marginal usefulness in a
    threads design can be worked around in other ways. Both #12 and #13
    were done to simplify the code and improve readability and maintain-
    ability. (As were most all of these changes)

TODO:

1) Rewrite most of the vnode pager to use VOP_GETPAGES/PUTPAGES. Doing
   this will reduce the vnode pager to a mere fraction of its current size.

2) Rewrite vm_fault and the swap/vnode pagers to use the clustering
   information provided by the new haspage pager interface. This will
   substantially reduce the overhead by eliminating a large number of
   VOP_BMAP() calls. The VOP_BMAP() filesystem interface should be
   improved to provide both a "behind" and "ahead" indication of
   contiguousness.

3) Implement the extended features of pager_haspage in swap_pager_haspage().
   It currently just says 0 pages ahead/behind.

4) Re-implement the swap device (swstrategy) in a more elegant way, perhaps
   via a much more general mechanism that could also be used for disk
   striping of regular filesystems.

5) Do something to improve the architecture of vm_object_collapse(). The
   fact that it makes calls into the swap pager and knows too much about
   how the swap pager operates really bothers me. It also doesn't allow
   for collapsing of non-swap pager objects ("unnamed" objects backed by
   other pagers).
1995-07-13 08:48:48 +00:00
David Greenman
06cb725951 Moved call to VOP_GETATTR() out of vnode_pager_alloc() and into the places
that call vnode_pager_alloc() so that a failure return can be dealt with.
This fixes a panic seen on NFS clients when a file being opened is deleted
on the server before the open completes.
1995-07-09 06:58:03 +00:00
Rodney W. Grimes
9b2e535452 Remove trailing whitespace. 1995-05-30 08:16:23 +00:00
David Greenman
5f55e84104 Accessing pages beyond the end of a mapped file results in internal
inconsistencies in the VM system that eventually lead to a panic. These
changes fix the behavior to conform to the behavior in SunOS, which is
to deny faults to pages beyond the EOF (returning SIGBUS). Internally,
this is implemented by requiring faults to be within the object size
boundaries. These changes exposed another bug, namely that passing in
an offset to mmap when trying to map an unnamed anonymous region also
results in internal inconsistencies. In this case, the offset is forced
to zero.

Reviewed by:	John Dyson and others
1995-05-18 02:59:26 +00:00
David Greenman
c3cb3e12f5 Moved some zero-initialized variables into .bss. Made code intended to be
called only from DDB #ifdef DDB. Removed some completely unused globals.
1995-04-16 12:56:22 +00:00
David Greenman
6c534ad868 Fix logic bug I just introduced with the flags to msync(). 1995-03-25 17:44:03 +00:00
David Greenman
1e62bc6357 Disallow both MS_ASYNC and MS_INVALIDATE flags being set at the same time
in msync().
1995-03-25 17:36:00 +00:00
David Greenman
e6c6af1149 Added "flags" argument to msync, and implemented MS_ASYNC and MS_INVALIDATE.
The MS_ASYNC flag doesn't current work, and MS_INVALIDATE will only toss out
the pages in the address space (not all pages in the shadow chain).
1995-03-25 16:55:46 +00:00
David Greenman
8f4e17d4b2 Fixed bug in vm_mmap() where the object that is created in some cases
was the wrong size. This is the likely cause of panics reported by
Lars Fredriksen and Paul Richards related to a -1 blkno when paging
via the swap_pager.

Submitted by:	John Dyson
1995-03-22 05:08:41 +00:00
David Greenman
bc9ad24756 Disallow non page-aligned file offsets in vm_mmap(). We don't support this
in either the high or low level parts of the VM system. Just return EINVAL
in this case, just like SunOS does.
1995-03-21 10:15:52 +00:00
David Greenman
fbcfcdf7db Fixed bug in the size == 0 case of msync() caused by a bogus return value
check..
1995-03-21 02:54:04 +00:00
David Greenman
edf8a81561 Removed redundant newlines that were in some panic strings. 1995-03-19 14:29:26 +00:00
Bruce Evans
b5e8ce9f12 Add and move declarations to fix all of the warnings from `gcc -Wimplicit'
(except in netccitt, netiso and netns) and most of the warnings from
`gcc -Wnested-externs'.  Fix all the bugs found.  There were no serious
ones.
1995-03-16 18:17:34 +00:00
David Greenman
c4ed5a07a5 Fixed obsolete comment. 1995-03-12 08:11:34 +00:00
David Greenman
f2da180f8e Fixed object reference count problem that occurred in the MAP_PRIVATE
case after we rewrote vm_mmap(). Added some comments to make it easier
to follow the reference counts.
1995-03-07 17:27:49 +00:00